Ultrasonic devices



United States Patent 3,488,851 ULTRASONIC DEVICES Zoltan Haydn, 810Tyler St., Hollywood, Fla. 33020 Filed Apr. 18, 1968, Ser. No. 722,454Int. Cl. A61c 1/06, 3/03; H01v 7/00 US. Cl. 32-58 1 Claim ABSTRACT OFTHE DISCLOSURE An ultrasonic device of the handtool type comprising amagnetostrictive stack, a horn functioning as an impedance transformerwith means for cooling the magnetostrictive stack and discharging thecoolant under pressure at the work area through the horn, thestack-horn-tool assembly being contained within two telescopingenclosures with proximal and distal caps.

This invention relates to ultrasonic devices.

The embodiment described in the within specification and disclosed inthe annexed drawing is a dental device useful for various types ofdental treatment or surgery. Basically such devices as they have beenheretofore designed comprise a power source and a handpiece containing amagnetostrictive stack to provide ultrasonic energy for a tool usablefor removing tartar and stains from a dental patients teeth and forother dental procedures, such as packing amalgam in cavities, curettage,dental surgery and the like. The numerous different types of operationto be performed require the utilization of differing toolconfigurations. One of the expedients which is generally employed forthe interchange of tools in the handpiece is to provide tools havingthreaded connections to the stack. In this arrangement, the insertion ofthe tool into the stack requires the use of a wrench, or its equivalent,and, as the tool and stack are vibrating longitudinally at a very rapidrate, eflicacious threading presents difiiculties.

An alternative design comprises the employment of an integratedstack-tool assembly, removable as an entirety from the handpiece, with africtional engagement between the enclosure for the stack and theexterior of the handpiece.

Additionally, the rapid impact of the tool on the tooth surface or othermedium upon which work is being performed, generates heat within thedental patients mouth which must be dissipated, and it is conventionalto transmit a coolant to the work surface. This is usually done by aconduit, exterior to the stack, terminating in the region of the workingpart of the tool. However, in some arrangement, the generation of heatwithin the stack causes a heat rise in the fluid to the extent that ifall of the fluid is passed to the patients mouth the quantum of heat isuncomfortable. Thus arrangements are added to bypass a portion of thefluid from the patients mouth and discharge it separately. A certainquantity of fluid is desirable for reasons other than its coolingeffect, as the impinging of the fluid on the work surface results incavitation within the fluid and the implosion of very small bubbles,which facilitate the work.

I have found it desirable to connect the tool permanently to themagnetostrictive stack, and in this invention have disclosed means forrapidly connecting and disconnecting the tool and stack from the holdertherefor to eliminate the problem created by the threaded connectionsbetween the tool and stack without incurring the disadvantages followingthe employment of the press-fit between the stack enclosure and thecasing of the handpiece.

Further, I have found that the eflicacy of the fluid in its performancein the operation is increased by so arranging the duct work that theoutput for the fluid is at the base of the working surface of the tool,whatever configuration it may have for the particular operation to be'performed.

Another object of the invention is to provide a tool of the typedescribed having a minimum of components, with resultant simplicity ofmanufacture and assembly and, naturally reduction in cost to the user,in which the components are so arranged so that the tool is properlybalanced and of such a weight that it can be used continuously by theoperator without fatigue. These and other objects of the invention willbe more particularly hereinafter described.

In the drawings,

FIG. 1 is a side elevational view of the device, with a cord forattachment to the power supply and fluid source, not shown;

FIG. 2 is a view in section through the center-line of the handleportion of the device, broken into three different sections and partshowing the solenoid in section part in plan, and part with the solenoidremoved;

FIG. 3 is a plan view of the stack with attached horn, or, as it issometimes referred to, acoustical matching transformer, and one of theforms of tools usable therewith;

Referring now to FIG. 2, the device comprises a flexible cable, C,having a jacket, J, which contains a pair of electrical lines, L, and aduct for the input of fluid, 'D. The lines are connected to a powersource not shown, and the duct to a fluid source under pressure,likewise not shown. The tool comprises a casing indicated generally at10, FIG. 1, having at its proximal end a proximal cap 11, with a centralopening 12, FIG. 2, for the lines L and duct D, and at its opposite end,a tubular enclosure 20. The casing 10 is shown in section in FIG. 2, andhas smooth internal surfaces at both its proximal and distal ends forpress-fits with the proximal cap 11 and the tubular enclosure 20. Thetubular enclosure 20 has an internal threading at its distal end forconnection with a distal can 47, having a central opening through whichthe tool T protrudes.

Within the casing and surrounding the tubular enclosure 20 is asolenoid, shown at 30 in section and at 31 in side elevation in FIG. 2.It should be understood that the winding of the solenoid is continuousthroughout the space 24 between the casing 10 and the tubular enclosure20,-from the point 33 near the base to the point 32 at the distal end ofthe casing. Thus the solenoid surrounds the entire length of themagnetostrictive stack 40 shown in the elevation in FIG. 3.

Referring further to FIG. 2, it will be noted that the proximal cap 11,has an internal axial opening 12, tapered with the smallest portion ofthe opening at the outer point of the cap with the taper enlarging theopening as it proceeds inwardly. Further provided is a ferrule 13, toclamp the jacket, I, of the cable, the lines L and the duct D, being fedthrough the internal opening of the ferrule 13, for connection with thesolenoid and cooling space, hereinafter to be described.

The tubular enclosure 20, has an external taper at 21, a stepped portion22, and an internal tubular portion 23, spaced from the walls of thecasing 10, to provide a space 24. At the portion of the tubularenclosure 20 nearest the proximal cap 11, are a pair of flanges, 25, 26,for engagement with the wall of the casing 10, and a base 27, having acoaxial channel 28, terminating in a nipple 29, for engagement with theduct, D. The flanges, 25, 26, are provided with openings for theelectrical lines L, so that they can be electrically connected to thesolenoid 30.

Referring specifically now to FIG. 3, the stack is formed of a series ofsheets of a magnetostrictive material consisting of laminations inphysical contact with one another except for oxide coatings, acquiredwhen they are annealed, which electrically insulate the laminations fromone another, thus decreasing the eddy current losses, Themagnetostrictive stack is brazed at the end nearest the base and affixedby brazing to a horn or acoustical impedance matching transformer 41 ofa stepped type, the acoustical performance of which is well understood,see for example, Belford, The Stepped Horn, Clevite Technical PaperTP-214, pages 814 through 822, and addendum, and similar literature. I

The nodal region of the horn 41, is approximately at the pointdesignated N, FIG. 3, at which point I locate a first O-ring 42, whichnot only serves as a seal to prevent the transmission of any escapingliquid beyond that point, but likewise as a nodal support for the horn.

The fluid operational aspects of the system are as follows. Fluid underpressure is transmitted into the region around the magnetostrictivestack 40 through the duct D, where it has a cooling effect. By reason ofthe circuitry described in co-pending application Ser. No. 722,485 filedApr. 18, 1968, of John M. Eubanks, concurrently filed, when usedconjointly with my invention, the heat rise in the magnetostrictivestack is less than in other prior art structures so that the quantum offluid required for the dissipation of the heat is less. This permits theuse of smaller duct work than would otherwise be the case and theprovision of the duct work through the horn which will now be described.

At the base of the horn, I have an inlet 44, shown in dotted lines, FIG.3, which proceeds normal to the axis of the horn where it intercepts atright angles an axially centered duct, likewise shown in dotted lines at45, FIG. 3, throughout the length of the horn to the outlet 46, at theinner face of the working surface of the tool T.

To provide an additional seal, I have included a second O-ring, 43, at apoint near the base of the horn and immediately beyond the inlet 44, forthe disposal of fluid circulating in the space between the tubularportion 23, of the tubular enclosure 20, and the magneto-strictivestack. This second O-ring, 43, seats against the internal shoulder 48 inthe tubular enclosure 20, when the distal cap 47 is fully engaged withthe internal threads of the tubular enclosure 20.

I have found that by the arrangement described, the fluid is deliveredto a point where its eflicacy is at an optimum through the cavitationprocesses in implementing the work being done by the tool. By reason ofthe exposure of the fluid to the heated stack, it is gently warm so thatit subjects the mouth of the dental patient to a pleasant reaction.

It will be obvious, of course, to persons skilled in the art thatnumerous variants of the arrangements I have hereby described arepossible.

Having fully described my invention, I claim:

1. An ultrasonic dental device comprising in combination,

a magnetostrictive stack joined to an acoustical horn of the steppedtype,

said horn functioning as an impedance transformer,

with the low impedance section of the horn terminating in a tool,

a fluid input near the junction between the high impedance section ofthe horn and the magnetostrictive stack, leading to a conduit extendingthrough the horn and terminating in an outlet in proximity to the tool,

a groove in the high impedance section of said horn beyond said input inwhich a second O-ring is seated,

a tubular enclosure for the stack and horn, having a proximal and adistal end, and having in its proximal end a fluid inlet originatingfrom a nipple into an internal cavity in which the stack is located, andhaving near its distal end a shoulder, beyond the stack and beyond thefluid input in the base of the horn, against which the second O-ring isseated,

a first O-ring located near the node of the horn,

said tubular enclosure being internally threaded at its distal end, and

an externally threaded distal cap, said external threads being adaptedto engage the internal threads at the distal end of the tubularenclosure,

said distal cap having an internal bore of small diameter surroundingthe low impedance section of the horn, a second bore of larger diametersized to encompass the high impedance section of the horn, and abevelled shoulder between said large and small bores adapted to seat thefirst O-ring near the node in the horn, when the distal cap is fullyengaged with the tubular enclosure,

said tubular enclosure having an external shoulder near its distal endforming a cylindrical portion having a diameter less than the diameterof the distal end, and a flange at its proximal end of the same diameteras the cylindrical portion near the distal end of the tubular enclosure,the space therebetween being adapted to form a cavity in the region ofthe magnetostrictive stack to receive and contain a solenoid,

a solenoid in said cavity, encircling said stack,

a casing of tubular configuration having a proximal and a distal end,the inner diameter of the casing at its proximal end having a press-fitwith the flange at the proximal end of the tubular enclosure, and asimilar press-fit at the cylindrical portion near the distal end of thetubular enclosure, the outer diameter of said casing being the same asthe outer diameter near the shoulder at the distal end of the tubularenclosure,

openings for electrical lines through the flange at the proximal end ofthe tubular enclosure, and,

electrical lines connected with a source of electrical energytherethrough and connected with the solenoid,

a proximal cap with a central opening having an outer diameter of thesame dimension as the outer diameter of the casing and the distal end ofthe tubular enclosure, and adapted to be press-fitted within theproximal end of the casing,

said central opening in said proximal cap providing clearance for thepair of electrical lines to the solenoid and for a fluid conduit to thenipple at the proximal end of the tubular enclosure, said fluid conduitbeing connected to a source of fluid under pressure.

References Cited UNITED STATES PATENTS 2,990,616 7/1961 Balamuth et al32-26 3,075,288 1/1963 Balamuth et al 3258 3,368,280 2/1968 Friedman etal 3258 ROBERT PESHOCK, Primary Examiner US. Cl. X.R. 3. 2

